This project will attempt to develop methods for the simultaneous identification and quantification of plasma catecholamines and their metabolic products in small samples that have been applied to HPLC columns. A newly developed computer-controlled swept-potential electrochemical detector will be applied to this goal. Such methods would be of value in both research and clinical biomedical neurochemistry and would lead to a much more comprehensive understanding of adrenergic pharmacology. The swept-potential detector is the electrical analog of the multiwavelength detector recently introduced. The additional dimension of information (potential) obtained with this detector over a DC detector can be used to identify components and to resolve two coeluting components. In addition, the potential for maximum current response is crossed for all components within the potential range of the sweep, thus decreasing the time required to optimize a procedure and allowing the determination of multiple components in one chromatogram, each at its optimum potential. The detector can be operated in multiple modes, but the primary mode of operation is with square-wave voltammetry. A wall-jet flow cell with platinum working electrode will be used. Such a cell has a fast response which is necessary for application of pulsed voltammetric techniques. In order to eliminate fouling and deactivation, the working electrode will be cleaned and activated periodically by application of extreme positive pulses followed by negative pulses. Preliminary experiments will be performed separately on the voltammetric and chromatographic processes. After combination of these techniques, the methods will be optimized and then evaluated with real samples.